Lifting-jack



UNITED STATES PATENT OFFICE. i

HARVY GRAY, OF BRISTOL, CONNECTICUT.

LIFTING-JACK.

Specification of Letters Patent No. 16,238, dated. December 16, 1856.

To all whom t may concern:

Be it known that I, HARVY GRAY, of Bristol, county of Hartford, and State of Connecticut, have invented a new and useful Improvement in Lifting-Jacks; and I do hereby declare that the same as described and represented in the following specification and drawings is suilicient to enable others skilled in the art to make and use the same.

I will proceed to describe the construction and use, referring to the drawings in which the same letters indicate like parts in each of the figures. 4

The nature of my invention consists, in so constructing and arranging, the several parts, that the weight suspended or lifted, may be moved horizontally; either way in the direction of the rollers action, and any movement which might occur by any unforeseen course prevented by `means of a pawl and ratchet, on each end of the roller, arranged, to operate in opposite directions from each other, at will.

In constructing and manufacturing my lifting jacks, I do not confine myself to any particular form, or shape except so far as relates to the general principle, of my invention.

Letter a, represents the side and edge elevation of my improvement; Z), the base; c, the recess aperture extending downward through the base; d, an enlarged portion in the form of a hub, or nut in or through which, the lifting screw, E, is fitted; F, are yokes in which the rollers G, are secured; the lower one is inserted through the recess aperture, through the base, and elevation, the screw entering the upper portion of said yoke, at 7L, and secured by a collar and nut. The upper bridle or yoke .is made, as represented at J, in a detachable manner, having an orifice fitting to a dowel pin, on the ends of the screw in such a way, as to allow the screw to turn freely while the weight rests upon the roller, and can be easily removed, and a pad y', substituted, when desirable, in its stead. The screw E, is made at the head, round or square, shape, with holes for the purpose of inserting a lever, or applying a wrench to operate the screw. The rollers G, are made with ratchets 7c on each edge;

reversed from each other. The yokes are supplied also with a pawl z', on each side; arranged so as to drop into the notches, in such manner as to prevent the movement of the rollers either way, till the pawl o-n one side or the other is lifted; one of which, always preventing a movement in the opposite direction from that which, the operator wishes. The upper pawl, f, or roller g, is designed for a high lift, the lower one for a low lift.

Having described the construction I will proceed to show its operation. I wish to raise and move, a building a short distance. I therefore place my jacks, at suitable distance apart; with timbers underneath the building and supplied with iron plates to prevent indentation of the rollers; thereby prevent obstructing the rolling motion. I then turn the screw until I get the desired height the weight resting entirely upon the rollers or jack. Then lifting the pawl on that side, where motion is required, the weight may be easily moved, whereas if the building was screwed up in the ordinary manner, it would be diflicult to produce a horizontal motion; also, in case a train of cars were oif the track, with one or two rails of railroad iron at hand I place one of them through the yoke, upon the roller and block up underneath, and by turning up the screw to a suitable height I am able easily to replace the car upon the track. By this arrangement I am able to accomplish in less time, with less help, than I could with those in common use and at the same time obtain a horizontal motion in connection with a perpendicular lifting motion.

I do not claim the screw, yoke, rollers, pawl, or ratchet, separately considered; for I am aware they are in use for various uses; but

What I do claim as my invention, and deside to secure by Letters Patent .is-

The employment of the screw E, yoke F, rollers G, pawls z', ratchets 7c, in combination substantially and for the purpose as hereinafter set forth and described.

HARVY GRAY. [n s] Witnesses:

It. G. DRAKE, CEAS. R. CHAPMAN. 

